The carbon neutral essay
 
 
 



Green sand - the answer to global warming?

In the New Scientist last week, I read the text of a lecture given by a Professor of Climatology concerning climate change in a time of Covid 19.  He wants us to try to capitalise on the massive changes to our lives as a result of the virus.  He wants us to persuade our government to stop things going back to how they were. As he points out, for three months we stopped flying, we drove our cars far less and used public transport barely at all, because we werenít going to work or to the shops. We all saw the difference in the emissions produced, indirectly at least, when we looked into a clear sky, and some even saw mountains from astonishing distances. In fact, our global CO2 emissions dropped by about 17% during the month of April and we can reasonably assume that May and June were similar.

Of course, things are gradually getting back to normal and so if things revert to how they were, then it is estimated that, in the absence of another lock-down, the overall decrease for 2020 as compared to 2019 is likely to be about 5%. This means that we would have the same emissions as in 2006.  As against this, as an industrialised country, we have committed to reduce our emissions by 80% by 2050 to get to net zero and so limit the global temperature rise to 1.5%.  And weíre not on track.  And itís all made worse by because the population is still increasing. It is likely to increase by 25%, stabilising at around 10 billion in about 2050 - our net zero year. But net zero is only step one. We will need thereafter actually to suck out far more CO2 from the atmosphere, meaning negative global emissions post 2050 for a human population of a size the world has never seen before.


So then, what to do? Stay at home? Ride bikes? The difficulty is that to be meaningful, as we know, itís not just our own energy consumption that we have to reduce, but every countries emissions.  But some are countries which are only just beginning to use significant amounts of energy and will need to use even more just to bring them within sight of the economic development weíve already benefited from. So then can we get over the difficulty by planting trees? It is already factored in but wonít be anywhere near enough, particularly when most tree planting seems to be done by way of carbon offsetting for the use of private jets by millionaires. Although progress is being made, planting trees to offset the emissions of heavy industry doesnít seem to have become quite as fashionable. It doesnít help either when large swathes of forest around the world are still being felled, even if itís done in order to make way for the production of food crops.

Countries attitudes to their Paris obligations vary very much. In particular, we have to wonder what the massive country of China will do. The Communist Party is under tremendous pressure because it is not able to give its citizens, deprived of liberty, at least the comfort of a growing standard of living. The ruling party in India is under similar pressure and coming from an even lower development base. Differences in emissions reductions have been allowed for in the Paris Agreement, but I have to say that I am not very optimistic that China, in particular, will abide by its treaty commitments. If the ruling party sees itself to be in danger of losing control if it complies with the Paris accord, then I think itís pretty obvious what the result will be.


Altogether not a very encouraging picture.  So is there any light at the end of this very long tunnel?  Obviously there is the reduction in the price of green energy, but we still have a long way to go to be able to store it for when the wind doesnít blow or the sun doesnít shine.  And as noted before, there are not enough raw materials available to allow sufficient batteries to be manufactured for this purpose.  Can we create a hydrogen based economy?  Well, weíre not making much progress towards it. So then, if we are to avoid a reduction in our living standards, not only will we have to insulate our homes, those relatively few that are still uninsulated, but we shall have to rely on the scientists to help us out with some new ideas. Fortunately, it seems there are one or two in the pipeline. By coincidence, articles appeared early this month in La Repubblica and then a few days later in the Guardian dealing with astonishingly simple proposals from different research groups, although both are based on essentially the same science. They suggest that igneous rocks, molten rock spurted up from the magma, may be our salvation. It seems that we can use the rock in its various forms to extract carbon dioxide permanently from the atmosphere.

So how and on what scale will this be possible?  The chemistry first. The rock in question, Bauxite, comes in various forms, but is rich in Magnesium Silicate mixed with a number of other metal compounds, including Calcium.  Water, whether in the form of rain or sea-water, is actually a very dilute concentration of Carbonic Acid, formed when carbon dioxide dissolves in it. This starts a reaction going with the rock which results in the formation of calcium carbonate Ė lime. So then, the rain falling onto the outcrops of basalt around the world is already a part of the carbon cycle, acting to remove carbon dioxide from the rain and so from the atmosphere. Itís just that it does it very slowly, because of the small surface area of the bauxite exposed to the rain. The proposal is to produce what would be bauxite sand or dust. In this way, it is possible to increase the surface area immeasurably.  All you have to do is spread it somewhere where it will come into contact with either rain or ocean. This is where the two research groups proposals diverge. 

First, the pretty option.  A variety of bauxite called Olivine is a translucent green. The idea is to spread the green grains of olivine on unused beaches and allow the oceans tides to wash over it.  The resulting Calcium Carbonate would be washed out to sea where it could be used to create coral or by molluscs and suchlike to create shells and so eventually drift to the ocean floor.  Turning 2% of the worldís beaches green could remove the whole annual man-made output of CO2.  Alternatively, we could simply spread the admittedly less pretty bauxite dust on farm land around the world. It removes CO2 from the atmosphere as the rain falls on it. The end product of lime is the same, which is beneficial for making the soil more fertile, as are the silicates released in the process.  And as bauxite is one of the most widespread rocks on our planet, itís also very cheap. There is a cost to reducing it to sand or dust, but this is already done in connection with its extraction as a raw material for building works. In fact there are mountains of bauxite dust with no obvious current use. So then whatís not to like for farmers everywhere?

And so with all of these possibilities open to us, I donít really see why we should have to bother too much about global warming - if our governments get on with the solutions which are already available to them.  Itís a problem which can be solved and at a relatively modest cost. The difficulty perhaps will be resistance amongst those new puritans of the green movement who wish us to wear hair shirts, not only to keep us warm, but as a sign of our sinfulness in burning fossil fuels in the first place. They take the extraordinary position that it was intrinsically wrong to do so, even though the overall benefit to us as a society from having built up our industry is so clear. So clear that, as already noted, the Paris Accord accepted the demands of the other less developed countries for leeway in making carbon emissions cuts in order to catch up with the rest of us.  So then, although puritanism has an attraction to a certain mind-set, Iím afraid that I am of a different mind. If we can get away without diminishing our standard of living and at the same time avoid global warming, then Iím all for it.  My hair shirt stays in the cupboard.

Paul Buckingham

14 July 2020







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